For 0.65, f(x) = 0.65x.
For the other scale, g(x) = 0.05 + 0.05x.
You now have two linear equations.ou c
Draw a graph and decide what is best deal by comparing.
I don't plan to draw the graph, but it is relatively simple.
The criteria for "which is best" can then be determined.
Or if you prefer lists of numbers, you can compare f(x) to g(x) for increasing values of x.
The graph is more fun because you will get a feel for how the functions behave just by looking at the graphs on same coordinate system.